Torsional joint



July 3, 1945.

H. M. DODGE TORSIONAL JOINT Filed Aug. 5, 1942 INVENTOR Howard M Dodge ATTORNEYS Patented July 3, 1945 General Tire &' Rubber Co acorporation of Ohio Application August 3, 1942, Serial No. 453,355

I 2 Claims. This inventionrelates to torsional joints and to a method of making the same. It particularly relates to a method of assembling a rubber sleeve between two annularly spaced telescoping metal members in the form of sleeve in such a manner that the rubber is held between the metal members in, a condition of substantial tension throughout the mass thereof.

. It has heretofore been proposed to effect con nection between two metallic sleeves by slipping a section of heavy walled rubber tubing along a tapered space into the space between inner and outer sleeve members to compress and elongate the rubber into frictional engagement with each of the sleeve members. In assembling rubber members in this manner where surface movement is had between the rubber and the sleeve members, it is almost essential that a lubricant such as soap be applied to the sliding surface. It has also been found that due to-the sliding action of the assembly, strain applied to various parts of the rubber is not at all uniform and that some joints prepared by sliding assembly fail prematurely.

It is an object of the present invention to pro vide a rubber articulated joint between two annularly, spaced telescoping metal members in which the rubber or rubberlike material is under relatively uniform compressive stress throughout.

It is another object of the present invention to provide rubber articulated joints between telescoping metallic sleeves in which the entire mass of rubber is 'under relatively uniform tension due to compression between said sleeves, and in which the side edges of the compressed rubber occup substantially the position with respect to the mass thereof as they occupied in the nudeformed rubber.

It is still another object of the present invention to provide a method of making stable rubber articulated joints between telescoping metallic members wherein slipping movements between the surface of the metal members and the surface of the rubber member are substantially eliminated during assembly. I

It is another object of the present invention to provide a method of assembling rubber articulated torsional joints between telescoping cylindrical metal sleeves wherein the rubber is incorporated between said sleeves without appreciable sliding movement and without the necessity of utilizing a lubricant.

It is a still further object of the present invention to provide a method of assembling rubber flexible bearing blocks suitable for use as fixed pany, Akron, Ohio,

supports or as joints between relatively movable members having telescoping metallic members joined by rubberlike material under high compression, wherein the rubberlike material is incorporated between the concentric metallic members with substantial elimination of sliding movement between the surface of the rubber material v and the metallic members.

Other objects will be apparent from the following description of the invention as illustrated b the drawing in which:

Figure i is an elevational view of a mandrel having rubber of cylindrical section wound spirally thereon for curing in open steam, so that rubber rings having a substantially round section may be readily and economically prepared;

Fig. 2 is a sectional view on the line 2-2 of Fig. lshowing the preferred shape of an extruded strip of rubber for winding around the mandrel to produce a substantially round section when wound thereon;

Fig. 3 is an elevational view of a modified form of apparatus which may be used in obtaining the deformable rings preferably used in the practice of the present invention;

s Fig. 4 is an elevational view, partly in section,

of a portion of apparatus used in assembling the joints of the present invention; showing the inner and outer sleeves and the annular elastic ring in position for the first step of the assem bling process;

Fig. 5 is a similarwiew showing. the position of apparatus and the members of the joint at the end of the assembling operation;

Fig. 6 is an elevational view, with parts broken away, of a joint member embodying the present invention; and

Fig. 7 is anelevational view, partly in section, of a portion of a modified form of apparatus, showing in solid lines joint members in position for assembling and in broken lines the joint in.

assembled position.

In accordance with the present invention, an annular deformable elastic member usually of rubber or vulcanized rubber-like material and of substantially round section, preferably having a volume so that the rubber is in just suflicient member, which is usually a sleeve, is provided with a removable tapered tip or leader member of the desired length to cause the elastic material or rubber member to make one or more complete revolutions so that in its final position the side edges of the elastic material, compressed between the joint members, occupy their molded positions with respect to the main mass of rubbery material, so that they are less subject to oxidation. Thus the some portion of the rubber forms theside edges of the deformed material and the undeformed material.

Referring to the drawing, in which like parts are designated by the same numerals of reference throughout the several views, and more particularly to Figs. 1 through 5, an annular elastic member I may be prepared by continuously extruding a strip 2 of rubberlike material and winding it upon a suitable mandrel 3, which has a spiral groove 4 with a rounded surface, curin the wound strip in a suitable medium, such as in a steam chamber (not shown), separating each turn of cured rubber from the other, and adhering two ends of the separate turns together to form a generally toroidal annulus. Separation of the turns is preferably accomplished by applying a cut through each turn longitudinally of the axis of the mandrel.

The strip 2 is preferably extruded in an eggshaped or slightly elongated section as illustrated in Fig. 2, so that when the strip is bent and applied to the mandrel it will have a round cross section.

The annular elastic member I is preferably of generally toroidal shape with a murmur substantially round half cross section. If desired, the member I may be molded in toroidal form in a suitable mold, such for example as illustrated in Fig. 3.

The molding apparatus of Fig. 3 comprises a plurality of mold members 5, each having an annular groove of a diameter corresponding to the mean diameter of the elastic members I. .The

mold members 5 may be assembled on a bolt 6 to form a. toroidal cavity by the coaction of the grooves in each pair of mold members 5. Suitable rubber material is placed in the groove of the mold members and pressure applied by tightening of a nut I against a spring 8. The mold apparatus is immersed in a heating medium to cure the rubber therein and produce the annular elastic members I in toroidal shape.

In the preparation of joints embodying the present invention, use is preferably made of a suitable press having a platen I0 and a plunger I I optionally movable toward and away from each other and capable of exerting substantial pressure on elements inserted between the platen I0 and plunger II. The inner member of the joint may be a cylindrical sleeve I2 and may be carried on the outer tip l3 of the plunger II. A leader member I4 is preferably applied to the leading end of the sleeve I2. The leader membber I4 may have a tail portion I5 adapted to fitwithin the sleeve I2 so that the shoulder I5 bears against the leading end'of the sleeve I2. The leading end of the leader member I4 is provided with atapered tip I1 to facilitate entry of the leader member into the opening I8 of the annular elastic member I. The tip I! of the leader may have a. fastening portion 20 which is frictionally held within a bore 2I-ln the leading end of the cylindrical body of the leader member I4. Means such as spacing washers I9 are preferably provided for adjusting the effective length of the cylindrical body of the leader member I4 so that the annular elastic member I will be positioned as desired between the inner sleeve I2 and the outer sleeve 22 when the members I2 and 22 are telescoped in position concentric with each other, as hereinafter described.

The upper or forward end of the shell or outer sleeve 22 carries a removable mounting member 23 having a tapered inner opening 24. The lower portion of the mounting member is bored to receive one end portion of the outer rigid element or sleeve 22. A shoulder 25 of the mounting member 23 is adapted to bear upon the upper end of the shell or outer sleeve 22. The lower inner diameter of the opening 24 adjacent the shoulder 25 is smaller than the diameter of the opening at the upper edge of the member 23 and preferably is substantially equal to the inner diameter of the member 22. The length of the tapered portion of the member 23 may be so chosen that the annular member I will be rotated in the desired position within the member 22 without appreciable surface sliding.

In the assembly of the joint or bushing, the

annular elastic member I, which is composed of vulcanized rubber or vulcanized rubberlike material such as synthetic rubber, is disposed within the mounting member 23 with its outer surface portion bearing against the conical or tapered surface of the inner opening 24. The tip I1 of the leader member I4 and the inner member of the sleeve I2 are then successively pressed'into the central opening of the generally torroidal elastic member I, which is of substantially round cross section without sharp corners, causing the rubber of the member I to move in a rotatable manner through .a tapered path of gradually decreasing cross-sectional area until the desired portion of the sleeve I2 is telescoped into the outer cylindrical sleeve 22. The leader member I4 and the tip I1 extend into an opening 21 of the plate III, as shown in Fig. 5. Since the members I2 and 22 are assembled with insideout rotation of the elastic member I, it is seen that sliding between surface portions of the rubberlike material ber 23 by the number of washers 3|, so that-the rubberlike material makes one or more complete rotations in the assembly of the joint and the exposed edges are under no strain other than that produced by compression of the rubber between the untapered inner and outersleeve members.

When the joint is assembled as shown in Fig. 7, it is seen that the edge portion bears the same relation to. the mass of deformable material as it did when vulcanized. The rubberlike material is under stress identical with that obtained by expanding or deforming the diameter of the inner opening I8 of the annular elastic member to correspond with the outer diameter of the tube I2, simultaneously contracting the outer diame is substantially eliminated. While the annular elastic member la in the joint i ter of the annular elastic member to correspond with the inner diameter of the outer sleeve or shell 22 without rotating or sliding movement of the member I.

Joints produced in accordance with the present inventionhave high fatigue resistance. Although the rubberlike material is under high stress, the joints are stable and the inner and outer sleeves do not tend to move longitudinally relative to each other when the assembling pressure is removed. Since lubricant is not necessary between the rubber or the rubberlike material and the inner and outer elements, slippage of the inner member with respect to the outer member is had, if had at all, only under exceedingly high deformations, and the entire relative movement between the rigid elements is taken up by strain in the rubberlike material. Rubberlike material In preferably does not extend substantially beyond one of the inner or outer sleeves, whichever is shorter.

The joint members of the present invention may be used as bearing blocks, in spring shackles,

in tank treads, or in any other application where ter of the outer element.

parting from the spirit of this invention as defined in the appended claims.

'What I claim is:

1. A joint having substantially concentric substantially untapered inner and outer elements separated by an intervened annulus of rubber which spaces them apart under substantial radial stress, the strains in said rubber being substantially identical with those obtained when an annular elastic member of substantially round cross section and the same volume is shaped by deforming the inner opening thereof so that the diameter corresponds with the outer diameter of the inner element and by simultaneously deforming the outer diameter'thereof so that this diameter corresponds with the inner diameter of the outer element. A

2. A joint having substantially concentric inner and outer cylindrical elements separated by an intervened annulus. of Tubber which spaces them apart under substantial radial stress, the strains in said rubber being substantially identical with those obtained when an annular elastic member of substantially round cross section and the same volume is shaped by deforming, without rotating and without surface slippage of the elastic material, the inner opening thereof so that the diameter corresponds with the outer diameter of the inner element and by simultaneously deforming the outer diameter thereof so that this diameter corresponds with the inner diame- HOWARD M. DODGE. 

